Conventionally, data processing devices such as word processors, personal computers, and portable information terminals have generally been provided with input means which allow a user to indicate a discretionary position on a display screen. Examples of such input means include the mouse, slide pad, and pen-shaped input device. Using this kind of input means, the user can perform such actions as indicating various processing operations, inputting images, etc.
With regard to processing in a data processing device like those mentioned above, whereby a user, using the input means, can draw a discretionary drawing, Japanese Unexamined Patent Publication No. 7-200152/1995 (Tokukaihei 7-200152/1995), for example, discloses the following touch panel input electronic device. When an erase mode (delete mode) is selected, this touch panel input electronic device performs processing which displays a predetermined figure centered on the position of the pen as detected by a coordinate detecting section, and erases the image within the displayed figure.
In this kind of touch panel input electronic device, when inputting a discretionary drawing using hand-drawn input, the following problems arise. FIGS. 9(a) through 9(b) are explanatory drawings showing the state of processing when using hand-drawn input to draw a telephone.
First, assume that, after confirming, that a draw/erase button A is in the draw mode, a telephone main body, receiver, and spiral cord connecting the receiver and the main body are drawn, as shown in FIG. 9(a).
Next, assume that a telephone cord is drawn extending from the lower left portion of the telephone main body, as shown in FIG. 9(b).
At this point, to change the point of connection of the telephone cord and the telephone main body to the upper right portion of the telephone in order to prevent the telephone cord and the spiral cord from crossing, the draw/erase button A is selected, thus switching to erase mode, as shown in FIG. 9(c). Then the telephone cord drawn in FIG. 9(b) is traced over using the pen P, as shown by the broken line in FIG. 9(c). In this way, the telephone cord drawn at the lower left portion of the telephone main body is erased.
However, as shown in FIG. 9 (d), in accompaniment with erasure of the telephone cord drawn at the lower left portion of the telephone main body, parts of the spiral cord and the telephone main body drawn adjacent to the telephone cord are also erased. Consequently, it is necessary to switch back to the draw mode by selecting the draw/erase button A, and then re-draw the erased parts of the spiral cord and telephone main body.
In this way, in hand-drawn input of a drawing, when two lines cross, erasing one line also causes part of the other line to be erased. Consequently, it is necessary to re-draw part of the other line, which has the drawback of making operations troublesome.
Again, Japanese Unexamined Patent Publication No. 8-163528/1996 (Tokukaihei 8-163528/1996), for example, discloses an image transmission system, in which a plurality of data processing devices are mutually connected, and through which users in separate locations view a common image, and attempt to reach understanding by mutually indicating in real time certain points on the image.
Again, Japanese Unexamined Patent Publication No. 7-21099/1995 (Tokukaihei 7-21099/1995), for example, discloses the following hand-drawing transmission method. This hand-drawing transmission method, as ink data are produced, produces text data and figure drawing commands, both of which are made of data structures having common features with the ink data, and performs real time transmission and display in predetermined data units of the ink data in a composite state with at least one of the text data and the figure drawing commands. By this means, it is possible to perform useful and efficient transmission among a plurality of pen computers capable of hand-drawn input, and for a group of users to edit a common text and drawing simultaneously.
When, as in the foregoing hand-drawing transmission method, a plurality of users edit a common drawing through transmission among a plurality of pen computers, a problem which arises is that it becomes impossible to distinguish which user drew which lines of the drawing on the display screen.